How to use it
- Enter length, width, and thickness of the slab.
- Enter the price per cubic yard of concrete you plan to pay.
- Click Calculate to see volume, bag count, and estimated cost.
Enter the slab’s length, width, and thickness, then the price you pay per cubic yard of concrete. The calculator converts the dimensions to cubic feet, then to cubic yards, and multiplies by your price to show the estimated cost. It also tells you how many 80‑lb bags you’ll need, using the fact that each bag yields about 0.6 cubic feet. Seeing the cubic‑yard volume helps you compare contractor quotes, while the bag count lets you order the right amount of mix. For example, a 12 ft × 10 ft slab 4 in thick equals 40 cubic feet (≈1.48 cubic yards) and needs about 67 bags. The “Estimated cost” line shows the total dollars, while “Cubic yards” and “Cubic feet” let you verify the volume. Use the results to budget, avoid over‑ordering, and keep your project on schedule.
Pro tips
- Add 10% waste to the cubic‑yard volume before ordering.
- Always round up the bag count; you can’t buy a fraction of a bag.
- Order a full extra yard of concrete to cover unexpected variations.
- Double‑check that thickness is entered in inches and converted to feet.
Real-life examples
- A homeowner estimating material for a 12 x 16 ft garage slab.
- A contractor pricing a new patio foundation to compare vendor quotes.
- A DIY enthusiast planning a shed floor and needing exact bag numbers.
Case study
Mike needed a 10 × 12 ft slab 6 in thick for his workshop. Using the calculator he saw the volume was 60 cubic feet (≈2.22 cubic yards) and that he required 100 bags, costing $1,110. He ordered the exact amount, avoided a $200 overrun, and completed the project on budget.